BACKGROUND Intranasal corticosteroids are among the most effective treatments for perennial allergic rhinitis (PAR). Some individuals unable to tolerate aerosols may prefer an aqueous nasal spray. OBJECTIVE To determine the efficacy, safety, and antiinflammatory effects of an intranasal aqueous pump spray formulation of budesonide. METHODS Four hundred seventy-eight patients [257 adults, 221 children (6 to 17 years)] with PAR were randomized to budesonide aqueous pump spray (Rhinocort Aqua) 32, 64, 128, or 256 microg, or placebo once daily for 6 weeks. Patients recorded nasal/ocular symptom severity daily. Nasal cytology was evaluated at baseline and end of treatment. The study was powered only to evaluate the overall population for significance. RESULTS Following 6 weeks of treatment, significant differences from baseline in nasal index score (NIS)--sum of blocked nose, runny nose, and sneezing scores--were observed in the 32-, 64-, and 256-microg aqueous budesonide groups compared with placebo (P < or = .031). No dose response was found for changes in NIS. Significant reductions from baseline NIS were observed with 256-microg aqueous budesonide compared with placebo in the first 24 hours following treatment (P = .004). Aqueous budesonide also significantly reduced individual nasal symptoms in two or more of the active treatment groups (P < or = .035). Patients' overall treatment efficacy assessments showed significantly greater symptom control with aqueous budesonide (P < or = .006), and overall quality of life improved. Significantly greater decreases in eosinophils and basophils were found in aqueous budesonide-treated groups (P < or = .007). The frequency of adverse events was similar among all treatments. CONCLUSIONS Once daily aqueous budesonide is well tolerated and effective in relieving nasal symptoms and inflammation associated with PAR.